This invention relates generally to centrifuges and more particularly to an improved cover for a centrifuge rotor.
In many centrifuges the rotor is secured to a drive shaft by some type of threaded fastener. It is, perhaps, the most common practice to clamp the rotor against a shoulder provided on the drive shaft with a headed bolt or cap screw. Such a screw is sometimes called a rotor "tie-down" screw. In most cases, a hole is provided in the center of the rotor through which the tie-down screw extends, to engage a tapped hole in the end of the drive shaft. Another, somewhat less common arrangement is for the portion of the drive shaft above the shoulder to extend all the way through the center of the rotor. In this arrangement, external screw threads are provided on the end of the drive shaft which are engaged by a nut, called a rotor tie-down nut, which serves to clamp the rotor to the drive shaft.
During operation of the centrifuge, vibratory forces may be developed which have a loosening effect on threaded fastenings. It is generally necessary, therefore, to tighten the rotor tie-down screw or nut at least moderately tight to ensure safe retention of the rotor by the drive shaft during operation of the centrifuge. The user of the centrifuge must have a wrench for loosening and tightening the rotor tie-down screw or nut each time the rotor is to be removed or replaced on the centrifuge.
As various clinical and industrial centrifugation procedures require samples of differing volume as well as containers of differing size and shape, it is not uncommon for a centrifuge to be equipped with a complement of rotors. Each rotor may be adapted to a specific purpose such as to hold a particular type or quantity of sample container. The operations of some users require that they make frequent rotor changes. Therefore, it would represent a considerable convenience to such users if they could accomplish the removal and replacement of centrifuge rotors without using wrenches or other external tools. A solution to this problem is found in the improvements in centrifuge design provided by the present invention.